Efficient photon detectors using surface acoustic waves

An efficient photon detector based on the ambipolar transport of photogenerated electrons and holes by surface acoustic waves (SAWs) has been investigated. In the experiments, the photogenerated electrons and holes are separated and transported in a GaAs channel and electrically detected by a lateral p–i–n junction. We show that the acoustic transport efficiency improves by using biased metallic guides along the SAW beam to create independent transport channels for electrons and holes. By optimizing the photon absorption efficiency and the amplitude of the SAW field, we demonstrated overall transport efficiencies above 85% for transport lengths exceeding 200μm.